The work proposed in this application focuses on the role of neurotransmitter metabolism in the development of the nervous system of the fruit fly Drosophila melanogaster. Mutations which alter the normal functions of the enzymes acetylcholinesterase, choline acetyl transferase and glutamate oxaloacetic transaminase are often associated with structural abnormalities in the nervous system. We propose to use these mutations to specifically address the question of whether such abnormalities are a consequence of the failure of "normal" developmental processes or are a consequence of the inability of the system to be maintained (degeneration?). We will largely direct our efforts to the development of the visual system and of the antenna and its central projection. Data will be gathered using standard histological and neuroanatomical procedures from staged wild-type, pure mutant and genetic mosaic individuals. We will gather limited data on visual system function and will also undertake the isolation of new genetic material necessary to the investigation.